I've got a good one. I've done the searches but nothing else is like my problem.

I've got a 02 1500HD.

my 4wd intermittently works/doesn't work. if i try to shift to 4wd the light flashes, I can hear the front diff actuator shift, then it lights the 2wd light and i can hear the front actuator shift back...no 4wd.

-I've tried pulling both fuses to reset.
-I've unplugged and reconnected the connectors thinking a bad connection.
-I've cleaned the ground strap to frame connection.

sometimes it works, most of the time it doesn't.

and its not displaying 'service 4wd'.

any suggestions, the dealers around here are not the best. Encoder sensor? dash switch? Anybody had a similar problem?

Thanks
Chris

help! anybody have a similar problem.

Check the electric connector at the 4wd switch on the side of the transfer case where the linkage shifts it. Loose or corroded I would suspect. Also, eyeball the wiring at the Xfer case toward the front for rub through. The front actuator wiring goes thru that switch on the Xfer case.

I will check the harness for any rub through. I have checked the pins/sockets in the connectors and they are clean.

the thing that has me puzzled is no 'service 4wd' light on the dash??

I had the one of the gears break loose (split) from the shaft inside the electric actuator on the Xfer case (there are no user serviceable parts inside there:mad: ). That allowed it whir when activated and it still switched modes, basically it did everything but slide the fork in the Xfer case.

i was having a similar problem until i purchased the manual actuator with an in cab knob(Posi-Lok is the company). good luck